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Scientists have used images collected by NASA’s DART asteroid impact mission to paint a more detailed picture of their asteroid targets Didymos and Dimorphos. The research could help to better understand the formation and evolution of binary asteroids like this.
DART, which stands for “Double Asteroid Test,” only impacted the smaller body in this two-asteroid binary system, the moonlet Dimorphos, which orbits the larger space rock Didymos. Still, the aim was to see what effect such an influence would have on the two bodies. The data collected during this successful mission could help scientists plan a planetary defense mission to divert an asteroid on a collision course with Earth.
Before crashing into Dimorphos on September 26, 2023, DART was able to take images of both near-Earth asteroids. Combined with data from the Italian Light Cubesat mission for Imaging Asteroids (LICIACube), the researchers were able to determine some of the geological features and physical properties of Didymos and Dimorphos.
The team, led by Olivier Barnouin of the Johns Hopkins University Applied Physics Laboratory, studied the surface of Didymos, the larger of the two asteroids. The researchers found that Didymos is rugged at high altitude with large boulders between 33 and 525 feet (10-160 meters) long and several craters. At low altitudes, the surface of this asteroid becomes smoother, with fewer rocks and large craters.
Its smaller moon companion, Dimorphos, has rocks across its surface that have a wider range of sizes. Although the Dimorphos surface is mostly craterless, it is riven with some cracks or “faults.”
The results helped Barnouin and his colleagues to determine that Dimorphos was probably formed from material that drifted away from Didymos and then coalesced under the influence of gravity.
The team used the number of craters on the two asteroids to measure the ages of the two asteroids. they determined that the parent body Didymos is 12.5 million years old, between 40 and 130 times older than Dimorphos. They estimated the age of the moon to be about 0.3 million years.
Related: NASA’s asteroid DART mission completely changed the shape of its target
Looking at the size of the boulders and their distribution across Dimorphos, a separate team of scientists led by Maurizio Pajola from the INAF – Padova Astronomical Observatory determined that they were formed at different times rather than all at the same time.
This suggests that the rocks on the surface of Dimorphos are directly inherited from Didymos, further supporting the idea that moons in binary asteroid systems form from material lost by their larger partners. This process also explained a distinctive ridge at the equator of the mother body, Didymos.
Another team of researchers led by Naomi Murdoch from the Université de Toulouse looked at boulder tracks traced across the surface of Didymos. They found that the Didymos surface is composed of very loose material, able to support much less weight than dry sand on Earth or lunar soil on the moon.
Meanwhile, Alice Lucchetti, from the Astronomical Observatory INAF-Padova and colleagues also found that boulders at the surface of Dimorphos are being broken over a period of about 100,000 years by a process called “thermal fatigue,” which results from a change in temperature that causes micro. -fractures in the rock.
Although 100,000 years seems like a very long time to us, in geological terms, it is a short time, especially in a solar system that is about 4.6 billion years old. This means that the thermal fatigue of Dimorphos is fast. This is the first time that rapid thermal fatigue has been observed on a rocky asteroid composed of silicate and nickel-iron materials.
A third team, led by Université de Toulouse researcher Colas Robin, compared 34 boulders on the surface of Dimorphos that ranged from 5.5 feet (1.67 meters) to 22 feet (6.7 meters) with rocks found on the loose asteroids “rubble “Itokawa. , Ryugu, and Bennu.
They found similarities between the rocky morphology of all these asteroids and suggested to Robin and colleagues a common mechanism of formation and evolution.
Related stories:
— Asteroid impact: This is the last thing NASA’s DART spacecraft saw before it crashed
— DART asteroid crash seen by James Webb, Hubble space telescope (photos)
— DART’s impact sent a tail of debris on asteroid Dimorphos thousands of miles long (great photo)
The team’s findings paint a detailed picture of the Didymos system as it was before the DART’s impact on Dimorphos. The results could help the European Space Agency’s (ESA) upcoming Hera mission.
Due to launch in October this year, Hera will meet Didymos and Dimorphos in September 2026. One of the Didymous binary system, Hera, will capture high-resolution data allowing a more comprehensive examination of the system as it is after the impact. DART. . This should help scientists better determine the outcome of DART’s collision with Dimorphos.
The three teams’ research papers were published on Tuesday (July 30) in the journal Nature.